Metastatic thyroid cancer with severe hyperthyroidism mimicking independent hyperfunctioning thyroid adenoma, showing transition to water-clear-tumour.
A case of different thyroid cancer is reported in detail, showing unusual behaviour both clinically and bioptically. The patient suffered from severe hyperthyroidism, with a scintigraphic finding of independent thyroid adenoma and simultaneous function in pelvic mass proved to be a metastasis of follicular thyroid cancer. Bioptical finding confirmed the aspiration biopsy conclusion that the independently functioning thyroid nodule had been in fact a follicular thyroid cancer. Microscopically, a transition of the usual type of follicular thyroid cancer to solid cancer consisting of water-clear cells was found. Thyroidectomy led to enhancement of uptake in pelvic metastasis but the general condition deteriorated rapidly leading to death by pulmonary embolism. The problem is discussed with regard to the development of hyperthyroidism in thyroid cancer.